The invention relates to an expandable retainer. More particularly, it relates to a reusable expandable retaining ring which may be expanded or stretched using a spanner or similar tool to install the ring over the head of a fastener whereupon on the release of the ring it reverts back to its normal shape and provides a retaining function against the head of the fastener.
In the past, a variety of washers and retaining rings have been used in a wide range of applications, with varying degrees of success. For example, U.S. Pat. No. 2,660,913 to Frisby discloses a two piece metallic retaining ring for use on shafts and the like which is expanded and installed using long round-nosed pliers inserted through holes in the outer spring coil of the ring. The conical embodiment of the Frisby retaining ring is also disclosed for resisting thrustloads while taking up end play between parts. In addition, U.S. Pat. No. 3,336,062 to Mekkes discloses a retaining ring consisting essentially of a band of non-metallic, torsionally resilient and flexable material having a generally D-shaped cross-section, for retaining e.g. two telescopically associated tubular members. The Mekkes retainer ring may be constructed either in a continuous annular form, or with one or more traverse gaps provided to avoid excessive overstressing of the ring. An alternative ring-like retainer or seal is disclosed in U.S. Pat. No. 3,134,613 to Regan which shows a quick connect shut-off device including an annular rubber collar which is slidable over and sealable against a tube end. The collar is made of an elastomeric material configured to form a fluid-tight engagement yet also designed to be readily disengageable and removable. U.S. Pat. No. 535,019, to Pipher et al is an early example of a hard washer for use on the spindles of vehicle axles and is especially intended to have high wear resistance.
Although these retaining devices may have been used in the past, each of these known devices is intended for a generally limited application. In addition, several of these known retaining rings are complicated and expensive to manufacture and can be difficult and time consuming to install and remove. Furthermore, although most known retaining rings are well suited for resisting axially applied force, they often have little resistance against torsional or bending loads.
Accordingly, it is an object of the invention to provide a novel retainer which may quickly and easily radially expand or bend to allow it to be installed over the head of a fastener or other article and then released so that it reverts to its natural shape and provides a retaining function.
It is also an object of the invention to provide such a retainer which is relatively well suited for resisting torsional and bending loads.
It is a further object of the invention to provide such a retainer which is simple in construction, inexpensive to manufacture, reliable and durable in use, and easy to install or remove.
It is a more particular object of the present invention to provide such a retainer which is generally universally adaptable to a variety of retaining applications.